1. Field of the Invention
The present invention relates to a flat light source and, particularly, to a field-emission-based flat light source.
2. Discussion of Related Art
Flat light sources are widely used in many fields, especially in display technology. Many light receiving display devices, such as liquid crystal displays (LCDs), need a flat light source to provide a uniform incidence light. Generally, a flat light source used in LCD converts a linear light source to a flat, area light source through an optical means. However, the conventional flat light source typically inefficiently utilizes light energy.
To improve the efficiency of the light energy utilization, a conventional field-emission-based flat light source is provided. The field-emission-based flat light source includes a cathode electrode, a transparent anode electrode spaced from the cathode electrode, and a fluorescent layer formed on the anode electrode. When a predetermined voltage is applied between the anode electrode and the cathode electrode, electrons are able to emit from the cathode electrode and move to the anode electrode. When the emitted electrons collide against the fluorescent layer, a visible light is produced and transmitted through the transparent anode electrode and to the outside as a flat, area light source.
However, in the conventional field-emission-based flat light source, light emits from the anode electrode directly. The potential non-uniformity of the thickness of the fluorescent layer and/or of the electron emission from the cathode may induce a non-uniformity of light emission of the fluorescent layer. Therefore, the uniformity of luminance of the conventional field-emission-based flat light source is decreased.
What is needed is to provide a field-emission-based flat light source, in which the above problems are eliminated or at least alleviated.